The academic study of medicinal plants for the treatment of diverse diseases has been nearly as pervasive as the study of Western medicines. The active principles from many traditional medicines have been extracted from plants, the curative agents identified and their mechanisms of action determined. Plant based medicines are typically well tolerated, with less severe side effects as well as a smaller range of side effects. In contrast, while synthetic drugs can be highly effective, their use is often hampered by severe side effects. Additionally, while synthetic pharmaceuticals are based upon single chemicals, many phytomedicines exert their beneficial effects through the additive or synergistic action of several chemical compounds acting at single or multiple target sites associated with a physiological process. As pointed out by Tyler (1999), this synergistic or additive pharmacological effect can be beneficial by eliminating the problematic side effects associated with the predominance of a single xenobiotic compound in the body. In this respect, Kaufman et al. (1999) extensively documented how synergistic interactions underlie the effectiveness of a number of phytomedicines.
This theme of multiple chemicals acting in an additive or synergistic manner likely has its origin in the functional role of secondary products in promoting plant survival. For example, in the role of secondary products as defense chemicals, a mixture of chemicals having additive or synergistic effects at multiple target sites would not only ensure effectiveness against a wide range of herbivores or pathogens but would also decrease the chances of these organisms developing resistance or adaptive responses (Kaufman et al., 1999; Wink, 1999). Conclusion: On one hand, synthetics may have the required efficacy for disease treatment; however this can be marred by severe side effects. On the other hand, despite the excellent medicinal qualities of many plants, they are individually insufficient to take chronic degenerative diseases into remission. However, there is mounting evidence which demonstrates that medical plants contain synergistic efficacy and/or side-effect neutralizing combinations (Gilani and Rahman, 2005). Thus, what are needed in the art are better treatment regimes with improved patient tolerance, while providing sufficient efficacy.